1. Field of the Invention
The invention relates to a film transport apparatus for transporting a film, which is a flexible sheet-like continuous material, and a film transport control method.
2. Description of the Related Art
A technique for transporting a film, which is a flexible sheet-like continuous material, such as a plastic film, a metal film, or a continuous paper, while supporting the film with a plurality of rollers has been suggested (which is, for example, described in Japanese Patent Application Publication No. 2001-343223 (JP-A-2001-343223)). Electrodes of a battery used in a hybrid car or an electric vehicle are handled in the form of a film in a manufacturing process. For a transport apparatus that transports the film, it is strongly required to increase a transport speed in order to reduce costs. In addition, to ensure quality, extremely high lateral position accuracy is required at the same time.
However, the lateral position varies due to misalignment of the roll or disturbance variations, such as variations in tension or speed, during transport. Thus, in the film transport apparatus, a guide roll is used to accurately control the lateral position of the film.
To correct the lateral position of the film the film tends to move so that the film is located perpendicular to the rotational axis of the guide roll if the guide roll is inclined with respect to the transport direction. As a result, the lateral position of the film is corrected.
However, in such a process of correcting the lateral position, it has been observed that wrinkling occurs in the film. The wrinkles degrade the quality of the product made of the film.